Hand-held electric heat sealer

ABSTRACT

A hand-held electric sealer used for sealing a plastic bag or the like, including a casing, a sealing mechanism, a press bar, and a safety device. The sealing mechanism has a heating wire, which produces heat for sealing the plastic bag or the like when turned on. The safety device controls the heating of the sealing mechanism, and stops the sealing mechanism from being triggered accidentally.

This is a continuation of application Ser. No. 09/208,256, filed on Dec.9, 1998 now U.S. Pat. No. 6,326,594 which is a continuation-in-part ofapplication Ser. No. 09/132,687, filed Aug. 12, 1998, now U.S. Pat. No.6,064,038 and Ser. No. 09/189,359, filed Nov. 9, 1998 now U.S. Pat. No.6,232,579 both of which are continuations-in-part of application Ser.No. 08/917,358 filed on Aug. 26, 1997, now U.S. Pat. No. 5,854,466, allof which are incorporated by reference in their entireties herein.

BACKGROUND OF THE INVENTION

The present invention relates to electric sealers, and more particularlyto a hand-held electric sealer with safety means which controls theheating of the sealing mechanism, and stops the sealing mechanism frombeing triggered by an erroneous action.

A variety of electric sealers have been developed, and have appeared onthe market. These conventional electric sealers are designed to beenergized by AC power supply, or DC power supply. U.S. Pat. No.5,142,123 discloses an electric an electric sealer energizable byinternal battery set or external AC adapter.

SUMMARY OF THE INVENTION

It is one object of the present invention to provide an electric sealerwhich is hand-held and safe to use. It is another object of the presentinvention to provide an electric sealer which is energizable by aninternal battery set or external AC adapter. It is still another objectof the present invention to provide a hand-held electric sealer whichincludes means to stop the sealing mechanism from being triggered by anerroneous action.

According to one embodiment of the present invention, the hand-heldelectric sealer comprises a casing, a sealing mechanism, a press bar,and safety means. The sealing mechanism comprises a heat insulativebase, a heating wire, and two metal locating plates. The heat insulativebase has a projecting block on the middle. The heating wire is mountedon the projecting block of the heat insulative base. The metal locatingplates are fastened to the heat insulative base at two opposite sides tohold down the heating wire. A heat resistive cover sheet may be fastenedto the projecting block of the heat insulative base, and covered on theheating wire. The number of the heating wire may be increased ifdesired. The heat insulative base of the sealing mechanism can be madeof ceramics, bakelite, heat insulative plastics, or any material thatresists heat as high as about 200° C. The press bar has one end, namelythe fixed end, pivotably connected to the casing, and an opposite end,namely the free end, mounted with a heat insulative block. When thepress bar is pressed down, the heat insulative block is lowered with thefree end of the press bar and forced against the heat insulative base ofthe sealing mechanism to clamp the mouth of the plastic bag, enablingthe mouth of the plastic bag to sealed. The safety means controls theheating of the heating wire of the sealing mechanism, and stops thesealing mechanism from being triggered by an accident. The safety meanscan be a stop plate pivotably to the outside wall of the casing, andturned between a first position where the stop plate is suspended abovethe sealing mechanism to stop the heat insulative block of the press barfrom contacting the projecting block of the heat insulative base of thesealing mechanism, and a second position where the stop plate is movedaway from the sealing mechanism for enabling the heat insulative blockof the press bar to be pressed against the projecting block of the heatinsulative base of the sealing mechanism. In an alternate form of thepresent invention, the safety means comprises a shaft mounted in a holeinside the casing, a stop rod turned about the shaft, and a knob fixedlyconnected to the stop rod and extended out of a notch on the casing andoperated by hand to turn the stop rod about the shaft between a firstposition where the sealing mechanism is not allowed to be triggered, anda second position where the sealing mechanism is allowed to betriggered. The safety means can be a safety switch, a press-buttonswitch, or an electric connector, or a combination of them. When apress-button switch is used, a protective shielding means is providedfor protection. The electric circuit is closed or, opened by operatingthe safety means of the safety switch, press-button switch or electricconnector. In still another alternate form of the present invention, thesealing mechanism is installed in the free end of the press bar.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded view of a hand-held electric sealer according to afirst embodiment of the present invention.

FIG. 2 is a perspective view of the first embodiment of the presentinvention.

FIG. 3 is a cross sectional view of the first embodiment of the presentinvention, showing the press bar not depressed.

FIG. 4 is similar to FIG. 3 but showing the press bar depressed.

FIG. 5 is an exploded view of a hand-held electric sealer according to asecond embodiment of the present invention.

FIG. 6 is an exploded view of a hand-held electric sealer according to athird embodiment of the present invention.

FIG. 7 is a top plain view of the third embodiment of the presentinvention, showing the arrangement of the electric circuit.

FIG. 8 is a sectional view of a part of the first embodiment of thepresent invention, showing an AC adapter inserted into the electricconnector, the second terminal disconnected from the first terminal.

FIG. 9 is an exploded view of a hand-held electric sealer according to afourth embodiment of the present invention.

FIG. 10 is a top plain view of the fourth embodiment of the presentinvention, showing the arrangement of the electric circuit.

FIG. 11 is an exploded view of a hand-held electric sealer according toa fifth embodiment of the present invention.

FIG. 12 is an exploded view of part of FIG. 11.

FIG. 13 is a schematic drawing showing the safety switch of the fifthembodiment of the present invention operated.

FIG. 14 is an exploded view of a hand-held electric sealer according toa sixth embodiment of the present invention.

FIG. 15 is a perspective view of the sixth embodiment of the presentinvention.

FIG. 16 is another perspective view of the sixth embodiment of thepresent invention when viewed from another angle.

FIG. 17 is an exploded view of a hand-held electric sealer according toa seventh embodiment of the present invention.

FIG. 18 is an exploded view of a hand-held electric sealer according toan eighth embodiment of the present invention.

FIG. 19 is an exploded view showing the detachable arrangement of thesealing mechanism according to the present invention.

FIG. 20 is a sectional view of an alternate form of the presentinvention, showing the sealing mechanism installed in the free end ofthe press bar.

FIG. 21 is similar to FIG. 20 but showing the press bar depressed.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to FIGS. 1–4, a hand-held electric sealer in accordance with afirst embodiment of the present invention is an electric sealerenergizable by an internal battery set, comprised of a casing 10, aspring holder 11, a press bar 20, a battery chamber 30, and a sealingmechanism 40.

The battery chamber 30 is defined within the casing 10, comprising afront contact holder 31 transversely disposed at a front side, a rearcontact holder 32 transversely disposed at a rear side, a pair of firstmetal contacts 33 and 34, bilaterally provided at the front contactholder 31, a pair of second metal contacts 35 bilaterally provided atthe rear contact holder 32, and two horizontal metal contacts 331 and341 respectively forwardly extended from the first metal contacts 33 and34. According to this embodiment, the second metal contacts 35 areintegral with each other battery set can then be installed in thebattery chamber 30 between the front contact holder 31 and the rearcontact holder 32 to provide DC power supply to the sealing mechanism40. The spring holder 11 is mounted in casing 10 between the horizontalmetal contacts 331 and 341.

The sealing mechanism 40 is mounted in the casing 10, comprising a heatinsulative base 42, a heating wire 42, two metal locating plates 43, aheat resistant cover sheet 44, and a compression spring 45. The heatinsulative base 41 comprises a flat projecting block 411 on the middle.The heating wire 42 is fastened to the projecting block 411 of the heatinsulative base 41. The locating plates 43 are fastened to the heatinsulative base 41 at two opposite sides to hold the heating wire 42 inplace. The heat resistant cover sheet 44 is covered on the projectingblock 411 and the heating wire 42 to protect the heating wire 42, and toprovide a smooth surface. The heat resistant cover sheet 44 can be ameshed member made of teflon-coated metal wire. The heat insulative base41 further comprises a bottom hole 412. The compression spring 45 has abottom end mounted in the spring holder 11, and a top end inserted intothe bottom hole 412. Therefore, the sealing mechanism 40 is supported onthe compression spring 45, and can be moved up and down relative to thecasing 10.

The press bar 20 comprises a heat insulative block 21 at the bottom sideof one end, namely the front end thereof, a heat resistant cover sheet22 covered on the heat insulative block 21, and a pair of lugs 23bilaterally arranged in parallel at an opposite end, namely the rear endthereof. The lugs 23 each have a pivot pin 231. The pivot pins 231 ofthe lugs 23 are respectively inserted into respective pivot holes 12 atthe rear side of the casing 10 remote from the sealing mechanism 40.Therefore, the press bar 20 is coupled to the casing 20, and can beturned up and down about an axis relative to the casing 10. When thepress bar 20 is turned downwards, the heat insulative block 21 ispressed on the projecting block 411 of the heat insulative base 41 ofthe sealing mechanism 40. The heat resistant cover sheet 22 is coveredon the heat insulative block 21 to provide a smooth surface. The heatresistant cover sheet 22 can be a meshed member made of teflon-coatedmetal wire. Further, a spring plate 24 is provided, having a fixed endfastened to the press bar 20 and a free end stopped at a part of thecasing 10. The spring plate 24 imparts an upward pressure to the pressbar 20, causing the press bar 20 to be maintained in an “opened”position where the heat insulative block 21 is kept away from theprojecting block 411 of the heat insulative base 41 of the sealingmechanism 40.

A safety stop plate 14 is pivotably connected to the front side of thecasing 10. When the safety heat sealer is not in use, the safety stopplate 14 is turned upwards and forced into the gap between the heatinsulative block 21 of the press bar 20 and the projecting block 411 ofthe heat insulative base 41 of the sealing mechanism 40 to prohibit theheat insulative block 21 of the press bar 20 from contacting the sealingmechanism 40. When in use, the safety stop plate 14 is turned outwardsand then downwards, enabling the heat insulative block 21 of the pressbar 20 to be pressed against the projecting block 411 of the heatinsulative base 41 of the sealing mechanism 40.

A cover 50 is covered on the casing 10 to protect the sealing mechanism40 and the battery chamber 30. The cover 50 is comprised of a frontcover plate 51, which covers the sealing mechanism 40, a battery coverplate 52, which covers the battery chamber 30, and a rear cover plate53, which covers the rear part of the casing 10. The front cover 51 hasan opening 511 through which the projecting block 411 of the heatinsulative base 41 of the sealing mechanism 40 passes.

Further, a magnetic mounting plate 13 is fixedly provided at the backside (bottom side) of the casing 10. By means of the magnetic mountingplate 13, the hand-held electric sealer can be secured to a metal objectfor example the metal wall of a refrigerator by magnetic attraction.

The operation of the first embodiment of the present invention isoutlined hereinafter with reference to FIGS. 3 and 4 again. Asillustrated in FIG. 3, when the hand-held electric sealer is notoperated, the metal locating plates 43 are kept away from the horizontalmetal contacts 331 and 341, the heating wire 42 is disconnected from theDC power supply of the battery (which is installed in the batterychamber 30), and the safety stop plate 14 is stopped between the heatinsulative block 21 of the press bar 20 and the projecting block 411 ofthe heat insulative base 41 of the sealing mechanism 40. Therefore,pressing the press bar 20 does not cause the sealing mechanism 40 towork. When in use, as illustrated in FIG. 4, the safety stop plate 14 isturned away from the projecting block 411, then the press bar 20 isdepressed to force the heat insulative block 21 against the heatinsulative base 41 of the sealing mechanism 40, causing the metallocating plates 43 to be lowered with the heat insulative base 41 intocontact with the horizontal metal contacts 331 and 341, and the heatingwire 42 is electrically connected to start the heat sealing operation.

When sealing the two thermoplastic flaps of an article, thethermoplastic flaps of the article are placed in between the heatinsulative block 21 and the projecting block 411, then the press bar 20is depressed to force the metal locating plates 43 into contact with thehorizontal metal contacts 331 and 341. When the metal locating plates 43touch the horizontal metal contacts 331 and 341, the heating wire 42 isturned on to produce heat, thereby causing the thermoplastic flaps ofthe article to be sealed. After sealing, the press bar 20 is releasedfrom the hand, enabling the heat insulative base 41 and the metallocating plates 43 to be moved upwardly away from the horizontal metalcontacts 331 and 341 by the compression spring 45, and therefore batterypower supply is cut off from the heating wire 42.

FIG. 5 shows a hand-held electric sealer according to a secondembodiment of the present invention. This embodiment is energizable byan external AC adapter. The structure and operation procedure of thissecond embodiment are similar to that of the aforesaid first embodimentwith the exception of the arrangement of power supply. The secondembodiment comprises a power socket 70 for receiving power supply froman AC outlet through an AC adapter. The power socket 70 has two oppositeterminals respectively connected to the horizontal metal contacts 331and 341 by electric wires 72 and 73. Because no battery is used, theaforesaid battery chamber can be eliminated from the casing 10.Therefore, the size of the casing 10 can be greatly reduced. Further,the safety stop plate 14 is pivotably connected to the outside wall ofthe casing 10 relative to the sealing mechanism 40 for safety control.

FIGS. 6 through 8 illustrate a hand-held electric sealer according to athird embodiment. This third embodiment can be energized by an internalbattery set or an external AC adapter as desired. The electricconnector, referenced by 90, comprises a first terminal 91, a secondterminal 92 and a third terminal 93 respectively connected to theleft-side first metal contact 33 and the two horizontal metal contacts331 and 341 by respective electric wires 71, 72 and 73. The left-sidehorizontal metal contact 331 and the left-side first metal contact 33are separated from each other. The right-side horizontal metal contact341 and the right-side first metal contact 34 are connected together. Asillustrated in FIG. 7, the first terminal 91 and the second terminal 92are electrically connected. When an AC adapter 80 is connected to theelectric connector 90, the second terminal 92 is forced away from thefirst terminal 91 (see FIG. 8), i.e., the battery is off afterinstallation of the AC adapter 80 in the electric connector 90.Therefore, only battery power or AC power is exclusively provided to thesealing mechanism at a time.

The aforesaid third embodiment further comprises a safety switch 60installed in the electric wire 72 between the second terminal 92 of theelectric connector 90 and the left-side horizontal metal contact 331.When not in use, the safety switch 60 is switched to off position to cutoff the power supply. Under this condition, pressing the press bar 20does not cause the sealing mechanism to work. Because the safety switch60 can easily be achieved by conventional techniques, it is notdescribed in detail.

FIGS. 9 and 10 illustrate a hand-held electric sealer according to afourth embodiment of the present invention. According to thisembodiment, the right-side horizontal metal contact 341 and theright-side first metal contact 34 are separated from each other, thefirst terminal 91 is connected to the left-side first metal contact 33by one electric wire 71, the second terminal 92 is connected to theleft-side horizontal metal contact 331 by one electric wire 72, thethird terminal 93 is connected to the right-side horizontal metalcontact 341 by one electric wire 73, and the safety switch 61 isinstalled in an electric wire 74, which is connected between theright-side first metal contact 34 and the right-side horizontal metalcontact 341.

FIGS. 11 through 13 illustrate a hand-held electric sealer according toa fifth embodiment of the present invention. This fifth embodimentcomprises a safety switch 100. The safety switch 100 is provided at thefront side of the casing 10, comprising a knob 101, an electricallyinsulative stop rod 102, and a shaft 103. The shaft 103 is mounted in ahole 16 inside the casing 10. The electrically insulative stop rod 102is a substantially V-shaped rod turned about the shaft 103. The knob 101is fixedly connected to a part of the stop rod 102, and extended out ofa top notch 17 at the front side of the casing 10. Further, a spring cap151 is covered on a spring 15 inside the casing 10, and forced upwardsby the spring 15 to support the Press bar 20 in the open position.

Referring to FIGS. 12 and 13 again, when not in use, the knob 101 isoperated by hand to turn the stop rod 102 about the shaft 103 to a firstposition where the two opposite ends of the stop rod 102 are suspendedabove the horizontal metal contacts 331 and 341 to stop the metallocating plates 43 from contacting the horizontal metal contacts 331 and341. On the contrary, when using the hand-held electric sealer, the stoprod 102 is turned about the shaft 103 to a second position where the twoopposite ends of the stop rod 102 are moved away from the horizontalmetal contacts 331 and 341, for enabling the metal locating plates 43 tobe lowered with the sealing mechanism 30 into contact with thehorizontal metal contacts 331 and 341. This safety switch 100 can beused in either of the aforesaid first, second and third embodiments, orany similar electric sealer.

FIGS. 14 through 16 illustrate a sixth embodiment of the presentinvention. According to this embodiment, the sealing mechanism isimmovable, i.e., the sealing mechanism cannot be moved vertically. Thehand-held electric sealer of the sixth embodiment is energizable by abattery set. According to this sixth embodiment, the sealing mechanism40 comprises a heat insulative base 41, a heating wire 42, two metallocating plates 43, and a heat resistant cover sheet 44. When assembled,the sealing mechanism 40 is disposed above the front contact holder 31,and the metal locating plates 43 are maintained in contact with thehorizontal metal contacts 331 and 341. The front cover plate 51 holdsthe sealing mechanism 40 in place, enabling the metal locating plates 43to be maintained in contact with the horizontal metal contacts 331 and341.

The aforesaid fifth embodiment further comprises a safety device, whichcan be a safety switch 75 or a press button switch 76. Both of thesafety switch 75 and the press-button switch 76 may be simultaneouslyinstalled. In this case, the heating wire 42 can be turned on only whenthe safety switch 75 and the press-button switch 76 are both switchedon. Referring to FIGS. 14–16 again, the left-side first metal contact 33and the left-side horizontal metal contact 331 are separately installedand an electric wire 721 is connected between the left-side first metalcontact 33 and the left-side horizontal metal contact 331. The safetyswitch 75 is installed in the electric wire 721 to switch on/off thecircuit. Alternatively, the right-side first metal contact 34 and theright-side horizontal metal contact 341 can be separately installed andconnected by an electric wire 731, and the press-button switch 76 can beinstalled in the electric wire 731 and controlled to close/open thecircuit. If desired, the second metal contacts 35 can be separated fromeach other, and connected by an electric wire in which the safety switchor press-button switch can be installed and operated to close/open thecircuit. The application of the safety switch and/or press-button switchcan be used in the aforesaid first embodiment.

Referring to FIG. 14 again, the sealing mechanism 40 can have aplurality of heating wires 42. The cross section of the heating wire(s)42 can have a circular shape, polygonal shape, or any of a variety ofshapes.

When the safety switch 75 is switched on, the two thermoplastic flaps ofthe article to be sealed are put in between the heat insulative block 21of the press bar 20 and the projecting block 411 of the heat insulativebase 41 of the sealing mechanism 40, then the press bar 20 is presseddown, and at the same time the press-button switch 76 is depressed byone finger, causing the heating wire(s) 42 to produce heat, enabling thetwo thermoplastic flaps of the article to be sealed. When thepress-button switch 76 is released, the heating wire(s) 42 is (are) off.After use, the safety switch 75 is switched off.

FIG. 17 shows a seventh embodiment of the present invention. Accordingto this embodiment, the sealing mechanism is immovable, and energizableby an AC adapter. As illustrated, a front contact holder 31, which holdstwo horizontal metal contacts 331 and 341, and a power socket 70 aremounted in the casing 10. The power socket 70 receives external powersupply, and has two opposite terminals respectively connected to thehorizontal metal contacts 331 and 341 by respective electric wires 72and 73. The aforesaid safety switch 75 and press-button switch 76 can beselectively installed in the electric wire 72 or 73, or connected inseries in the electric wire 72 or 73. Two or more safety switches orpress-button switches may be installed. When a plurality of safetyswitches or press-button switches are installed, the sealing mechanismcan be operated only when all safety switches or press-button switchesare switched on. The installation and operation of the switches of theseventh embodiment may be used in the aforesaid second embodiment.

FIG. 18 illustrates an eighth embodiment of the present invention. Thesealing mechanism according to this eighth embodiment is immovable, andenergizable by an internal battery set or an external AC adapter.According to this embodiment, the casing 10 comprises a battery chamber30 for holding a battery set. The battery chamber 30 comprises a frontcontact holder 31 transversely disposed at a front side, a rear contactholder 32 transversely disposed at a rear side, a pair of first metalcontacts, namely, the left-side first metal contact 331 and theright-side first metal contact 34 bilaterally provided at the frontcontact holder 31, a second metal contact 35 bilaterally provided at therear contact holder 32, and two horizontal metal contacts namely aleft-side horizontal metal contact 331 and a right-side horizontal metalcontact 341 respectively disposed in contact of the first metal contacts33 and 34. Please see also FIG. 8, an electric connector 90 is mountedin the casing 10. The electric connector 90 comprises a first terminal91, a second terminal 92, and a third terminal 93. The terminals 91, 92and 93 are respectively connected to the left-side first metal contact33, the left-side horizontal metal contact 331 and the right-sidehorizontal metal contact 341 by electric wires 71, 72 and 73. Before theinstallation of an AC adapter 80 in the electric connector 90, the firstterminal 91 and the second terminal 92 are electrically connected. Whenan AC adapter 80 is connected to the electric connector 90, the secondterminal 92 is forced away from the first terminal 91, i.e., the batteryis off after installation of the AC adapter 80 in the electric connector90. Therefore, only battery power or AC power is exclusively provided tothe sealing mechanism at a time. A safety switch and a press-buttonswitch (not shown) can be connected in series, and installed in theelectric wire 72. Alternatively, a safety switch and a press-buttonswitch may be connected in series, and installed in the positioncorresponding to the position of the safety switch 61 of the aforesaidfourth embodiment. The operations of the sealing mechanism, the safetyswitch and the press button switch are similar to the aforesaid sixthand seventh embodiments.

Referring to FIG. 19, the sealing mechanism can be made detachable. Asillustrated, the horizontal metal contacts 331 and 341 each have anupright lug 332 or 342, which has a locating hole 333 or 343. The metallocating plates 43 of the sealing mechanism 40 each have a bolt 431 atan outer side. By inserting the bolts 431 of the metal locating plates43 into the locating holes 333 and 343 at the metal contact plate 331and 341, the sealing mechanism 40 is coupled between the horizontalmetal contacts 331 and 341. Because the sealing mechanism 40 isdetachable, it can be replaced with a new one when its heating wire orheat resistant cover sheet is damaged.

Referring to FIGS. 20 and 21, the sealing mechanism 40 can be installedin the free end of the press bar 20. As illustrated, the press bar 20comprises two metal press plates 25 respectively connected to thesealing mechanism 40. The casing 10 comprises a heat insulative block 18at the top corresponding to the sealing mechanism 40 at the press bar20. A switch 19 is installed in the casing 10, and controlled to turnon/off the sealing mechanism 40. When the press bar 20 is pressed downto force the sealing mechanism 40 against the heat insulative block 18,the metal press plates 25 are simultaneously pressed on the switch 19,causing the switch 19 to be switched on, and therefore the electriccircuit is closed, enabling electricity to be transmitted to the sealingmechanism 40. In FIGS. 20 and 21, the sealing mechanism 40 is movablyprovided at the free end of the press bar 20 (the sealing mechanism 40is coupled to the free end of the press bar 20 and supported on a springmember). Alternatively, the sealing mechanism 40 can be fixedly securedto the free end of the press bar 20.

The design of arranging the sealing mechanism at the press bar can beused in any of a variety of hand-held electric sealers, includingbattery-operated electric sealers, AC electric sealers. AC/DC dual modeelectric sealers.

It is to be understood that the drawings are designed for purposes ofillustration only, and are not intended as a definition of the limitsand scope of the invention disclosed.

1. A hand-held electric sealer comprising a) a housing, b) a press barhaving a free end, said press bar being pivotally connected to saidhousing, c) a metal press plate remote from said free end of said pressbar for normally biasing said press bar in an open position, whereinsaid metal press plate is secured to said press bar, d) a heating unit,e) a source of current, and f) circuitry electrically connecting saidheating unit and said source of current, wherein said circuitry isnormally in an open state, wherein when said free end of said press baris pivoted downwardly said metal press plate switches said circuit froman open state to a closed state.